These common heterocyclic compound, 24241-18-7, name is 2-Amino-3,5-dibromopyrazine, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. Computed Properties of C4H3Br2N3
A 100-mL, three-neck flask was charged with 2-bromo-l,l-dimethoxyethane 4 (23.2 g (16 mL, 137.2 mmol) and aqueous HBr (47.6% HBr by wt, 8.8 mmol/mL, 6.6 mL, 58.8 mmol), and the reaction mixture was heated to reflux (55C) for 2 hours. The mixture was allowed to cool to 40C, and solid NaHCC3 was added in small portions, until evolution of gas ceased. The resulting suspension was filtered, under vacuum, into a 500-mL, three-neck flask, and the filter cake was washed with isopropanol (200 mL). Solid 3,5-dibromopyrazin-2-amine (3) (12.0 g, 47.2 mmol) was added into the isopropanol filtrate, and the reaction mixture was heated at reflux (78C) for 16 hours. The resulting suspension was cooled to room temperature, filtered, the cake was washed with cold isopropanol (100 mL), and then the cake was dried under vacuum. The cake was transferred into a three-neck flask, into which, water (200 mL) was added, followed by solid K2CC3, in small portions, until gas evolution ceased, after which the reaction was stirred for 30 minutes. The resulting precipitate was isolated by filtration, and washed with water (200 mL). The solid was dried at 50C, to constant weight, then dissolved in THF, filtered through a plug (celite, silica gel, and charcoal). The solvent was removed under vacuum, to give 12.0 g of the desired product (5) as a white solid at 99% purity, as determined by NMR and LC-MS. IH NMR (500 MHz, CDC13) delta 8.26 (s, IH), 7.84 (d, J = 1.0 Hz, IH), 7.78 (d, J = 1.1 Hz, IH); 13C NMR (126 MHz, CDC13) delta 136.93, 134.06, 120.29, 119.26, 115.78.
The synthetic route of 2-Amino-3,5-dibromopyrazine has been constantly updated, and we look forward to future research findings.
Reference:
Patent; DOW GLOBAL TECHNOLOGIES LLC; ROHM AND HAAS ELECTRONIC MATERIALS KOREA LTD.; ONDARI, Mark E.; WELSH, Dean M.; FROESE, Robert DJ; NA, Hong-Yeop; (38 pag.)WO2016/209895; (2016); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem